Chapter Introduction Land Biomes Lesson 2 Aquatic Ecosystems

Chapter Introduction Land Biomes Lesson 2 Aquatic Ecosystems Lesson 3 How Ecosystems Change Chapter Wrap-Up Dr. Marli Mill/Visuals Unlimited/Getty Images Lesson 1

How do Earth’s biomes and ecosystems differ?

What do you think? Before you begin, decide if you agree or disagree with each of these statements. As you view this presentation, see if you change your mind about any of the statements.

Do you agree or disagree? 1. Deserts can be cold. 2. There are no rain forests outside the tropics. 3. Estuaries do not protect coastal areas from erosion.

Do you agree or disagree? 4. Animals form coral reefs. 5. An ecosystem never changes. 6. Nothing grows in the area where a volcano has erupted.

Land Biomes • How do Earth’s land biomes differ? • How do humans impact land biomes?

Land Biomes • biome • taiga • desert • tundra • grassland • temperate

Land Ecosystems and Biomes • Scientists classify similar ecosystems in large geographic areas as biomes. • A biome is a geographic area on Earth that contains ecosystems with similar biotic and abiotic features. • Earth has seven major biomes: desert, grassland, tropical rain forest, temperate deciduous forest, taiga, and tundra.

Earth has seven major biomes.

Desert Biome • Deserts are biomes that receive very little rain. • They are on every continent and are Earth’s driest ecosystems. • Rainwater in deserts drains away quickly because of thin, porous soil. • Lizards, bats, woodpeckers, and snakes are among animals found in deserts.

Desert Biome (cont. ) • Shallow roots of desert plant life absorb water quickly. • Humans have an impact on deserts by using valuable water.

Grassland Biome • Grassland biomes areas where grasses are the dominant plants. • Wheat, corn, oats, and other important cereal crops grow in grasslands where deep fertile soil supports plant growth. • Grasslands have a wet and dry season.

Grassland Biome (cont. ) • Large herbivores such as bison and elk and predators such as hawks and coyotes live in North American grasslands. • Humans reduce habitat for wild species when they plow large areas of grassland to raise crops. • Hunting has reduced the number of large herbivores in many grasslands.

The temperatures vary depending on the season in the United States grasslands.

Tropical Rain Forest Biome • The forests that grow near the equator are called tropical rain forests. • They receive large amount of rain and have dense growths of tall, leafy trees. • Insects make up the largest group of tropical animals.

Tropical Rain Forest Biome (cont. ) People have cleared more than half of Earth’s tropical rain forests for lumber, farms, and ranches, where poor soil does not support rapid growth of new trees.

Temperate Rain Forest Biome • Regions of Earth between the tropics and the polar circles are temperate regions. • Temperate regions have mild climates with distinct seasons. • Temperate rain forests are moist ecosystems in coastal areas with rich, moist soil.

Temperate Rain Forest Biome (cont. ) • Forests are dominated by spruce, cedar, and redwood trees. • Fungi and small flowering plants grow on the moist forest floor. • Animals include mosquitoes, owls, deer, and bears. • Logging can destroy the habitat of forest species, but rich soil enables cut forests to grow back.

Temperate Rain Forest Biome (cont. ) In what ways do humans affect temperate rain forests?

Temperate Deciduous Forest Biome • Temperate deciduous forests grow in temperate regions where winter and summer climates have more variation than those in temperate rain forests. • These forests are the most common forest ecosystems in the United States. • They include mostly deciduous trees, which lose their leaves in the fall.

Temperate Deciduous Forest Biome (cont. ) • Summers are hot and humid and winter temperatures are often below freezing and snowy. • Some animals in temperate deciduous forests spend the winter in hibernation. • Humans have cleared thousands of acres of Earth’s deciduous forests for farms and cities.

Temperate Deciduous Forest Biome (cont. ) How are temperate deciduous rain forests different from temperate rain forests?

Taiga Biome • A taiga is a forest biome consisting mostly of cone-bearing evergreen trees that only exists in the northern hemisphere. • It occupies more space on Earth’s continents than any other biome. • Winters are long and snowy and summers are short, warm, and moist.

Taiga Biome (cont. ) Abundant insects in summer attract many birds, which migrate south in the winter.

Tundra Biome • A tundra biome is cold, dry, and treeless. • Winters are long, dark, and freezing, and summers are short and cool. The growing season is only 50– 60 days. • Permafrost is a layer of permanently frozen soil that prevents deep root growth.

Tundra Biome (cont. ) • Many animals hibernate or migrate south during winter. Few animals live in tundras year round. • Drilling for oil and gases can interrupt migration patterns.

• Earth has seven major land biomes, ranging from hot, dry deserts to cold, forested taigas. • Half of Earth’s species live in rain forest biomes. • Temperate deciduous forests are the most common forest biome in the United States.

Which type of biome has dry and wet seasons and grass as the dominant plant? A. desert B. tropical rain forest C. temperate deciduous forest D. grassland

In which type of biome does rainwater drain away quickly because of thin, porous soil? A. grasslands B. deserts C. a taiga D. tropical rain forests

Which is the most common forest ecosystem in the United States? A. temperate deciduous forests B. tropical rain forests C. grasslands D. tundra

Do you agree or disagree? 1. Deserts can be cold. 2. There are no rain forests outside the tropics.

Aquatic Ecosystems • How do Earth’s aquatic ecosystems differ? • How do humans impact aquatic ecosystems?

Aquatic Ecosystems • salinity • wetland • estuary • intertidal zone • coral reef

Aquatic Ecosystems • There are four major types of water, or aquatic, ecosystems: freshwater, wetland, estuary, and ocean. • Each type of aquatic ecosystem contains a unique variety of organisms. • Salinity is the amount of salt dissolved in water.

Aquatic Ecosystems (cont. ) Water in saltwater ecosystems has high salinity compared to water in freshwater ecosystems.

Freshwater: Streams and Rivers • Freshwater ecosystems include streams, rivers, ponds, and lakes. • Oxygen levels in streams are high because air mixes into the water as it splashes over rocks.

Freshwater: Streams and Rivers (cont. ) • Slow-moving river water has higher levels of nutrients and lower levels of dissolved oxygen than fast-moving water. Paul Nicklen/NGS/Getty Images • Soil that washes into a river from streams introduces nutrients such as nitrogen and can make river water muddy.

Freshwater: Streams and Rivers (cont. ) • Willows, cottonwoods, and other waterloving plants grow along streams and on riverbanks. • Runoff from cities, industries, and farms is a source of pollution. Dr. Marli Mill/Visuals Unlimited/Getty Images • Dams from hydroelectric plants stop the water’s flow.

Freshwater: Ponds and Lakes • Bodies of water like ponds and lakes form in low areas on land contain freshwater that is not flowing downhill. • Sunlight reaches the bottom of most ponds. • Lakes are larger and deeper than ponds and sunlight only penetrates the top few feet of water.

Freshwater: Ponds and Lakes (cont. ) • Plants surround ponds and lake shores and surface water contains plants and algae. Paul Nicklen/NGS/Getty Images • Organisms like insects, frogs, fish, and turtles live in shallow water near shorelines, but few organisms live in the deeper, colder water of lakes.

Freshwater: Ponds and Lakes (cont. ) Runoff from farms, gardens, and roads wash pollutants into ponds and lakes, disrupting food webs. How do ponds and lakes differ?

Wetlands • Wetlands are aquatic ecosystems that have a thin layer of water covering soil that is wet most of the time. • Wetlands contain freshwater, salt water, or both, and are among Earth’s most fertile ecosystems. • Freshwater wetlands form at the edges of lakes and ponds and in low areas on land.

Wetlands (cont. ) • Saltwater wetlands form along ocean coasts. Michael S. Quinton/National Geographic/Getty Images • More than one-third of North American bird species use wetlands for nesting and feeding.

Wetlands (cont. ) In the past, water was drained away from wetlands to build homes and raise crops, but today many wetlands are being restored and preserved. How do humans impact wetlands?

Estuaries • Estuaries are regions along coastlines where streams or rivers flow into a body of salt water. • Most estuaries form along coastlines, where freshwater in rivers meets salt water in oceans. • Salinity depends on rainfall, the amount of freshwater flowing from land, and the amount of salt water pushed in by tides.

Estuaries (cont. ) • Animals in estuaries include many species that people use for food, like oysters and clams. • Many species of birds depend on estuaries for breeding, nesting, and feeding. • Destruction of estuaries reduces habitat for estuary species and exposes coastline to flooding and storm damage.

Estuaries (cont. ) estuary from Latin aestuarium, means “a tidal marsh or opening”

Ocean: Open Oceans • The open sea, one type of ocean ecosystem, extends from the steep edges of continental shelves to the deepest parts of the ocean. • Photosynthesis can only take place in the uppermost, sunlit zones.

Ocean: Open Oceans (cont. ) • Overfishing threatens many ocean fish. • Trash discarded from ocean vessels or washed into oceans from land is a source of pollution.

Microscopic algae and other producers in the sunlit zone form the base of most ocean food chains.

Ocean: Coastal Oceans • Coastal oceans include several types of ecosystems, including continental shelves and intertidal zones. • The intertidal zone is the ocean shore between the lowest low tide and the highest high tide. • Nutrients washed in from rivers and streams contribute to high biodiversity.

Ocean: Coastal Oceans (cont. ) Intertidal species, like crabs, fish, and mussels, have adaptations for surviving exposure to air during low tides and to heavy waves during high tides.

Ocean: Coral Reefs • A coral reef is an underwater structure made from outside skeletons of tiny, soft-bodied animals called coral. • Most coral reefs form in shallow tropical oceans and protect coastlines from storm damage and erosion. • Coral reefs provide food and shelter for many animals, including shrimp, crabs, scallops, and clams.

• Wetlands can be saltwater ecosystems or freshwater ecosystems. • Coral reefs and coastal ecosystems have high levels of biodiversity. Paul Nicklen/NGS/Getty Images • Freshwater ecosystems include ponds and lakes.

Which type of zone describes the ocean shore between the lowest low tide and the highest high tide? A. twilight zone B. intertidal zone C. sunlit zone D. dead zone

What is the name for an underwater structure made from outside skeletons of tiny, softbodied coral? A. an intertidal zone B. an estuary C. a coral reef D. a coastal zone

Which of these do many species of birds depend on for breeding, nesting, and feeding? A. estuaries B. coral reefs C. intertidal zones D. the open sea

Do you agree or disagree? 3. Estuaries do not protect coastal areas from erosion. 4. Animals form coral reefs.

How Ecosystems Change • How do land ecosystems change over time? • How do aquatic ecosystems change over time?

How Ecosystems Change • ecological succession • climax community • pioneer species • eutrophication

How Land Ecosystems Change • Ecological succession is the process of one ecological community gradually changing into another. • The final stage of ecological succession in a land ecosystem is a climax community—a stable community that no longer goes through major ecological changes.

How Land Ecosystems Change (cont. ) • In a tropical forest biome, a mature tropical forest is a climax community. • Climax communities are usually stable for hundreds of years.

How Land Ecosystems Change (cont. ) What is a climax community?

How Land Ecosystems Change (cont. ) • Ecological succession in new areas of land with little or no soil, such as a lava flow or sand dune, is primary succession. • The first species that colonize new or undisturbed land are pioneer species.

How Land Ecosystems Change (cont. ) pioneer Science Use the first species that colonize new or undisturbed land Common Use the first human settlers in an area

How Land Ecosystems Change (cont. ) In areas where existing ecosystems have been disturbed or destroyed, secondary succession can occur.

How Freshwater Ecosystems Change • Freshwater ecosystems change over time in a natural, predictable process called aquatic succession. • In aquatic succession the buildup of decomposed remains accumulate over time as soil. • Eventually the water disappears and the area becomes land.

How Freshwater Ecosystems Change (cont. ) What happens to a pond, a lake, or a wetland over time?

How Freshwater Ecosystems Change (cont. ) Eutrophication is the process of a body of water becoming nutrient-rich. eutrophication from Greek eutrophos, means “nourishing”

How Freshwater Ecosystems Change (cont. ) • Eutrophication is a natural process, but humans contribute to it by introducing fertilizer, waste, and other nutrient-rich pollution to a body of water. • High nutrient levels support large populations of algae and other microscopic organisms that end up using most of the dissolved oxygen in the water, leaving less available for fish and other organisms.

• Ecosystems change in predictable ways through ecological succession.

• The final stage of ecological succession in a land ecosystem is a climax community.

• The final stage of aquatic succession is a land ecosystem.

What term refers to the first species to colonize new or undisturbed land? A. a climax community B. a pioneer species C. a stable community D. secondary succession species

What term refers to the process of one ecological community gradually changing into another? A. pioneer succession B. eutrophication C. ecological succession D. climax community

During which natural, predictable process do freshwater ecosystems change over time? A. ecological succession B. eutrophication C. secondary succession D. aquatic succession

Do you agree or disagree? 5. An ecosystem never changes. 6. Nothing grows in the area where a volcano has erupted.

Key Concept Summary Interactive Concept Map Chapter Review Standardized Test Practice

Each of Earth’s land biomes and aquatic ecosystems is characterized by distinct environments and organisms. Biomes and ecosystems change by natural processes of ecological succession and by human activities.

Lesson 1: Land Biomes • Each land biome has a distinct climate and contains animals and plants well adapted to the environment. Biomes include deserts, grasslands, tropical rain forests, temperate rain forests, deciduous forests, taigas, and tundras. • Humans affect land biomes through agriculture, construction, and other activities.

Lesson 2: Aquatic Ecosystems • Earth’s aquatic ecosystems include freshwater and saltwater ecosystems. Wetlands can contain either salt water or freshwater. The salinity of estuaries varies. Dr. Marli Mill/Visuals Unlimited/Getty Images • Human activities such as construction and fishing can affect aquatic ecosystems.

Lesson 3: How Ecosystems Change • Land aquatic ecosystems change over time in predictable processes of ecological succession. • Land ecosystems eventually form climax communities. • Freshwater ecosystems undergo eutrophication and eventually become land ecosystems.

What is a geographic area on Earth that contains ecosystems with similar biotic and abiotic features? A. desert B. biome C. temperate region D. tropical rainforest

Which biome is found on every continent and is Earth’s driest ecosystem? A. grasslands B. temperate regions C. polar regions D. deserts

Which ecosystem can contain freshwater, salt water, or both, and are among earth’s most fertile? A. grasslands B. wetlands C. estuaries D. coral reefs

Which food chain’s base is made mostly of microscopic algae and other producers in the sunlit zone? A. saltwater B. wetland C. ocean D. coral reef

Which term refers to the process of a body of water becoming nutrient-rich? A. aquatic succession B. ecological succession C. secondary succession D. eutrophication

What is the name forests that grow near the Earth’s equator? A. biomes B. deciduous forests C. a taiga D. tropical rain forests

Which of these is a forest biome consisting mostly of cone-bearing evergreen trees that only exists in the northern hemisphere? A. tundra B. taiga C. grassland D. temperate rain forest

Salinity is a measure of the amount of what substance dissolved in water? A. soil B. bacteria C. salt D. algae

What are the regions along coastlines where streams or rivers flow into a body of salt water? A. wetlands B. ponds C. lakes D. estuaries

Which term refers to the process of one ecological community gradually changing into another? A. aquatic succession B. ecological succession C. secondary succession D. primary succession